It's good-looking, hardy and less thirsty, so it should be widely grown

Sedges have edges. That's one way to tell a grass from a sedge. Years ago, when I was working at Ho'omaluhia Botanical Garden, our visionary boss Martha McDaniel landed a grant and brought in a top nature educator. Her name was Mrs. Terwillinger, and she had all kinds of "hooks" to make learning about plants fun, fascinating for keiki and memorable.

I still use the sedges-edges garden rhyme to explain the grass versus sedge matter. Sedges have triangular stems while grasses have flat stems. Some sedges have round or square stems. You can touch a sedge and feel its sharp edges.

Carex wahuensis is a native Hawaiian sedge that we could and should use more of in our landscapes. It is pretty and tough. It has a striking yellow- green color that can add "pop" to a garden landscape. It does well in dry, windy and rocky sites as well as in moist sunny, gardens, or in pots on a rugged lanai.

I was reminded of it at a recent Garden Club of Honolulu meeting, where Jeff Mikulina of the Sierra Club spoke about global warming and the simple steps we can take to combat it. After the meeting, gardener Mary Ann Bell shared a carex plant with me.

Club members are now growing display-quality carex plants, which will be later showcased in a growers' challenge tailored to teach people about some of our more obscure yet tough and gorgeous native Hawaiian plants.

If you look at a sedge in a pot at a nursery, you might not be impressed. If flowers are all you see or look for in a garden plant, you will be disappointed. But look at it in its subtle simplicity in a landscape or a restoration of native Hawaiian forest area and you will be impressed. The potential of this simple, tough, less-thirsty Hawaiian plant is impressive.

About four years ago, when my husband and I were teaching for the outreach college on Moloka'i, a student suggested that we visit the hilltop teaching garden of Richard and Bronwyn Cooke. This was a marvelous and inspiring experience in a Hawaiian dryland forest that was becoming more Hawaiian every day.

Under the canopy of Hawaiian koa (replacing old alien plantings of eucalyptus) was a beautiful yellow-green clumping plant. I had to look closely to identify this pretty-colored ground cover that was healing the land: It was carex, growing well, reseeding and looking simple and gorgeous.

Lyon Arboretum in Manoa also has some attractive and easy-to-maintain garden plantings of this sedge.

Because sedges are tougher than grasses, some say they have little economic use. Nut sedge is an alien, weedy nightmare in a perfectly manicured lawn. No matter how much you dig it out, the nuts will break off in little pieces and the plant will always pop up again.

But if you are a weaver, you likely love sedges. Some of the finest mats in old Hawai'i — Ni'ihau craft of makaloa mats — were made from a little native Hawaiian sedge called Cyperus laevigatus. The mat was made of the whole round stems of makaloa and was as bendable as cloth and used for pa'u, sleeping mats, and capes or cloaks. Kamehameha had a great cloak of finest makaloa. The ali'i Liloa had a fine loincloth, woven from the sedge makaloa.

'Uki or cladium is another sedge that grows in dryland and intermediate Hawaiian forest. Lei-makers and weavers love this large, leaves-clumping sedge with its pretty and dryable brown flower clusters.

Mau'u 'aki'aki, or Fimbristylis cymosa, is a cute little sedge that is growing very well on a beach-saving sand dune in a Lanikai garden. A professional team I worked with developed the land-protecting dune after resolving a small conflict with a contractor who wanted to haul sand away from a nearby property.

Our team planted natives on the dune. In old Hawai'i, coastal dunes protected many of our beaches. This precious sand is now mostly mixed with cement to make concrete. If Hawai'i residents endeavor to restore and protect the state's coasts with dunes and native plants, we might slow down our loss of vital sand and beaches.

'Ahu 'awa, or 'ehu 'awa, a Hawaiian sedge that gardeners grow in water gardens, was used to strain 'awa. Its scientific name is Cyperus javanicus. Papyrus of the Egyptian papermakers, Moses in the bulrushes is a sedge called Cyperus papyrus in scientific Latin. This ancient cultivated water plant is edible and used for fiber, rope and cordage.

Water chestnut is another type of sedge used for weaving of mats, baskets and hats.